This work is directed toward the development of new and efficient procedures for the synthesis of alpha-methylene cyclopentanone and alpha-methylene-alpha',beta'-epoxycyclopentanone derivatives which appear to be potential antitumor agents. As synthetic targets in this area we have chosen Methylenomycin A and B which are structurally very similar to the antibiotic Sarkomycin known to possess significant antitumor activity. Our synthetic approach to methylenomycin B, structurally the simpler of the two methylenomycins, calls for the elaboration of an alpha-methylene functionality onto 2,3-dimethyl-2,3-epoxycyclopentanone. The key step in this sequence requires generation of the kinetic enolates of either 2,3-dimethyl-2,3-epoxycyclopentanone or 2,3-dimethylcyclopentanone. Here model studies are envisioned in order to develop efficient methodology for the introduction of the alpha-methylene functionality. Synthetic approaches to Methylenomycin A will proceed along three lines. As with methylenomycin B, approach (a) calls for the introduction of the alpha-methylene into a preformed epoxycyclopentanone derivative. Approaches (b) and (c), on the other hand, consist of an initial photochemical cycloaddition of either gamma-crotonolactone or maleic anhydride to 2-pentyne. Subsequent ozonolysis of the cyclobutene adducts followed by aldol cyclization of the resultant 1,4-dicarbonyl systems leads to key bicyclic cyclopentenone intermediates. From these intermediates via two distinct pathways, we approach the synthesis of methylenomycin A.